In the finishing operations of drywall construction, tape is usually applied between adjacent pieces of drywall. Thereafter, compound such as plaster or joint compound is spread over the tape covering the drywall seams and over adjacent portions of the adjoining drywall pieces, to thereby fuse together the previously separate sections of drywall. Thereafter, in the usual fashion, joint compound or the like is applied over the remainder drywall surface area, where needed, to provide a finished product.
The conventional tool for the application of the joint compound over the tape adjoining adjacent drywall pieces has been a simple flat, straight knife made of metal. In using this conventional knife in the application and spreading of the joint compound over the tape and adjoining drywall segments, a multiple-step operation is necessary. The multiple-step operation has been necessitated by the fact that the knife in current use must be used to apply a large amount of the joint compound on the drywall segments, thereafter spreading it in an uneven fashion and, after that, smoothing it out which, by itself, takes usually two or more separate operations of sanding and spreading more compound to refill shrinkage of the previously applied layer of compounds. Thus, the actual spreading of the joint compound or the like over the tape, adjacent drywall segments, and the rest of the drywall as needed, has been tedious, time consuming and a multiple-step operation.
The very same knife that has been used to apply the joint compound or the like to the tape and adjoining wall portions has also been used to apply spackle to fill in cracks in a wall or ceiling before the painting of the surfaces. This also is a time consuming and multi-step operation, in the same manner as the above-described application of joint compound to drywall. In the application of the spackle to a crack, what is most important is to fill the crack with the spackle, and to thereafter insure that the wall portions adjacent on either side of the crack are made smooth. Using the conventional knife, this has been, as described above, a difficult task, since the application of the spackle is not done consistently and evenly over the crack and adjoining wall portions thereto.
U.S. Pat. Nos. 4,731,258 and 4,654,919 disclose the tool and method for spreading joint compound, cement or spackle on planar surfaces including drywall, upon which the present improvement invention is based. These patents teach the use of a spreader tool having two surfaces, a flat surface and a concave surface. The present invention improves upon the prior art by providing a flexible application edge, variable spreader surface rigidity, and an improved surface curvature to enhance single application compound use, and to improve upon the utility and maintenance features of the prior art spreader tools. Additionally, the flexible application edge can be removable and replaceable to adjust to varying surfaces and varied compound spreading needs.